diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 72ed22b..7aa9cf5 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -1308,6 +1308,7 @@
       DEBUG(errs() << "\tIncompatible source regclass: "
             << tri_->getName(DstSubReg) << " not in " << SrcSubRC->getName()
             << ".\n");
+      (void)DstSubReg;
       return false;             // Not coalescable.
     }
   }
diff --git a/lib/Transforms/Scalar/LoopUnroll.cpp b/lib/Transforms/Scalar/LoopUnroll.cpp
index 3250288..7d551f1 100644
--- a/lib/Transforms/Scalar/LoopUnroll.cpp
+++ b/lib/Transforms/Scalar/LoopUnroll.cpp
@@ -121,6 +121,7 @@
   BasicBlock *Header = L->getHeader();
   DEBUG(errs() << "Loop Unroll: F[" << Header->getParent()->getName()
         << "] Loop %" << Header->getName() << "\n");
+  (void)Header;
 
   // Find trip count
   unsigned TripCount = L->getSmallConstantTripCount();
diff --git a/lib/Transforms/Utils/LowerSwitch.cpp b/lib/Transforms/Utils/LowerSwitch.cpp
index 89adb98..17e40e1 100644
--- a/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/lib/Transforms/Utils/LowerSwitch.cpp
@@ -309,6 +309,7 @@
   DEBUG(errs() << "Clusterify finished. Total clusters: " << Cases.size()
                << ". Total compares: " << numCmps << "\n");
   DEBUG(errs() << "Cases: " << Cases << "\n");
+  (void)numCmps;
   
   BasicBlock* SwitchBlock = switchConvert(Cases.begin(), Cases.end(), Val,
                                           OrigBlock, NewDefault);